1. Field of the Invention
The present invention relates to friction coupling mechanisms such as brakes wherein a rotatable element is frictionally coupled to a relatively nonrotatable element and clutches wherein two relatively rotatable elements are coupled and uncoupled. More particularly the invention relates to friction coupling mechanisms wherein mercury is employed as hydraulic fluid in a force multiplying piston and cylinder assembly.
2. Description of the Prior Art
Hydraulic and hydraulic-pneumatic brakes and clutches having friction members driven outwardly in opposite directions to engage opposed discs have been described in Suppes et al, U.S. Pat. Nos. 3,237,738 and 3,311,205 and 3,584,717, as well as in Montalvo U.S. Pat. No. 3,696,900. The devices disclosed in those patents are compact and easy to service. The present invention incorporates advantageous features shown in the above identified patents.
The high density of mercury has suggested its use as a damping medium in a clutch, as in U.S. Pat. No. 771,771, or as the fluid in a centrifugal clutch. The use of mercury as a coolant in a slip clutch has been suggested in U.S. Pat. No. 3,695,407.
Despite the wide variety of prior art clutches and brakes, there continues to be a need for improved friction coupling mechanisms that combine compactness with high torque capability, especially for industrial applications where space is limited.